The shape of an ellipse is determined by its height and width.
A: ellipse thick line thin color gray left 70% from 2mm left of (A.w,A.n) line same from 2mm left of (A.w,A.s) text "height" at (7/8<previous.start,previous.end>,1/2<1st line,2ndline>) line thin color gray from previous text.n up until even with 1st line -> line thin color gray from previous text.s down until even with 2nd line -> X1: line thin color gray down 50% from 2mm below (A.w,A.s) X2: line thin color gray down 50% from 2mm below (A.e,A.s) text "width" at (1/2<X1,X2>,6/8<X1.start,X1.end>) line thin color gray from previous text.w left until even with X1 -> line thin color gray from previous text.e right until even with X2 ->
Curiously, the "radius" has no effect on the shape of an ellipse. The ellipse is determine solely by the width and height. If the width and height are equal, the ellipse degenerates into a circle.
Boundary points:
A: ellipse thin dot ".c" below at A dot ".n" above at A.n dot " .ne" ljust above at A.ne dot " .e" ljust at A.e dot " .se" ljust below at A.se dot ".s" below at A.s dot ".sw " rjust below at A.sw dot ".w " rjust at A.w dot ".nw " rjust above at A.nw